• Title/Summary/Keyword: temperature dependent material properties

Search Result 359, Processing Time 0.029 seconds

Nonlinear static analysis of functionally graded porous beams under thermal effect

  • Akbas, Seref D.
    • Coupled systems mechanics
    • /
    • v.6 no.4
    • /
    • pp.399-415
    • /
    • 2017
  • This paper deals with the nonlinear static deflections of functionally graded (FG) porous under thermal effect. Material properties vary in both position-dependent and temperature-dependent. The considered nonlinear problem is solved by using Total Lagrangian finite element method within two-dimensional (2-D) continuum model in the Newton-Raphson iteration method. In numerical examples, the effects of material distribution, porosity parameters, temperature rising on the nonlinear large deflections of FG beams are presented and discussed with porosity effects. Also, the effects of the different porosity models on the FG beams are investigated in temperature rising.

Electrothermal Crack Analysis in a Finite Conductive Layer with Temperature-dependent Material Properties (온도 의존성 물성치를 가지는 유한한 전도층에서의 전기/열하중을 받는 균열의 해석)

  • Jang Yong-Hoon;Lee Sang-Young
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.30 no.8 s.251
    • /
    • pp.949-956
    • /
    • 2006
  • The method of Greenwood and Williamson is extended to obtain a solution to the coupled non-linear problem of steady-state electrical and thermal conduction across a crack in a conductive layer, for which the electrical resistivity and thermal conductivity are functions of temperature. The problem can be decomposed into the solution of a pair of non-linear algebraic equations involving boundary values and material properties. The new mixed-boundary value problem given from the thermal and electrical boundary conditions for the crack in the conductive layer is reduced in order to solve a singular integral equation of the first kind, the solution of which can be expressed in terms of the product of a series of the Chebyshev polynomials and their weight function. The non-existence of the solution for an infinite conductor in electrical and thermal conduction is shown. Numerical results are given showing the temperature field around the crack.

Thermal buckling Analysis of functionally graded plates using trigonometric shear deformation theory for temperature-dependent material properties

  • Lazreg Hadji;Royal Madan;Hassen Ait Atmane;Fabrice Bernard;Nafissa Zouatnia;Abdelkader Safa
    • Structural Engineering and Mechanics
    • /
    • v.91 no.6
    • /
    • pp.539-549
    • /
    • 2024
  • In this paper, thermal buckling analysis was conducted using trigonometric shear deformation theory, which employs only four unknowns instead of five. This present theory is variationally consistent, and accounts for a trigonometric variation of the transverse shear strains across the thickness and satisfies the zero traction boundary conditions on the top and bottom surfaces of the plate without using shear correction factors. The grading is provided along the thickness of the plate as per power law volume fraction variation of metal-matrix ceramic reinforced composite. The non-linear governing equation problem was solved for simply supported boundary conditions. Three types of thermal loads are assumed in this work: uniform, linear and non-linear distribution through-the-thickness. It is well known that material properties change with temperature variations and so the analysis was performed for both the cases: temperature-dependent (TD) and temperature-independent (TID) material properties. The impact on thermal buckling for both linear and non-linear temperature variation was considered. The results were validated for the TID case with other theories and were found to be in good agreement. Furthermore, a comprehensive analysis was performed to study the impact of grading indices and geometrical parameters, such as aspect ratio (a/b) and side-to-thickness ratio (a/h), on the thermal buckling of the FG plate.

Improvement of thermal buckling response of FG-CNT reinforced composite beams with temperature-dependent material properties resting on elastic foundations

  • Bensaid, Ismail;Kerboua, Bachir
    • Advances in aircraft and spacecraft science
    • /
    • v.6 no.3
    • /
    • pp.207-223
    • /
    • 2019
  • Current investigation deals with the thermal stability characteristics of carbon nanotube reinforced composite beams (CNTRC) on elastic foundation and subjected to external uniform temperature rise loading. The single-walled carbon nanotubes (SWCNTs) are supposed to have a distribution as being uniform or functionally graded form. The material properties of the matrix as well as reinforcements are presumed to be temperature dependent and evaluated through the extended rule of mixture which incorporates efficiency parameters to capture the size dependency of the nanocomposite properties. The governing differential equations are achieved based on the minimum total potential energy principle and Euler-Bernoulli beam model. The obtained results are checked with the available data in the literature. Numerical results are supplied to examine the effects of numerous parameters including length to thickness ratio, elastic foundations, temperature change, and nanotube volume fraction on the thermal stability behaviors of FG-CNT beams.

Temperature-dependent Structural and Magnetic Properties of Diamagnetic $HgI_2$

  • Park, C.I.;Jin, Zhenlan;Hwang, I.H.;Yeo, S.M.;Han, S.W.
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2013.08a
    • /
    • pp.291.1-291.1
    • /
    • 2013
  • We examined the temperature-dependent structural and magnetic properties of HgI2 in the temperature range of 300~400 K. HgI2 is a diamagnetic material and can be used for X-ray or γ-ray detectors. DCmagnetization measurements on HgI2 showed that there is a small but distinguishable change in its diamagnetic properties near 375 K. The magnetic property change is not expected because Hg and I are known as nonmagnetic elements. X-ray diffraction (XRD) measurements revealed a structural transition in the temperature of 350~400 K. Temperature-dependent x-ray absorption fine structure (XAFS) demonstrated that the chemical valence states of both Hg and I did not changed in the temperature range of 300~400 K. However, XAFS revealed that the bond-length disorder was slightly increased in the temperature range, particularly, near Hg atoms. The structural changes of HgI2 are likely related to its diamagnetic property change. We will discuss the relation between the diamagnetic properties and local structural properties of HgI2 in detail.

  • PDF

Optimal Design of Functionally Graded Plates (경사기능재료 판의 최적설계)

  • Na, Kyung-Su;Kim, Ji-Hwan
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2006.05a
    • /
    • pp.1061-1064
    • /
    • 2006
  • Optimal design of functionally graded plates is investigated considering stress and critical temperature. Material properties are assumed to be temperature dependent and varied continuously in the thickness direction. The effective material properties are obtained by applying linear rule of mixtures. The 3-D finite element model is adopted using an 18-node solid element to analyze more accurately the variation of material properties and temperature field in the thickness direction. For stress analysis, the tensile stress ratio and compressive stress ratio of the structure under mechanical load are investigated. In the thermo-mechanical buckling analysis, temperature at each node is obtained by solving the steady-state heat transfer problem and Newton-Raphson method is used for material nonlinear analysis. Finally, the optimal design of FGM plates is studied for stress reduction and improving thermo-mechanical buckling behavior, simultaneously.

  • PDF

Thermal effect on axisymmetric bending of functionally graded circular and annular plates using DQM

  • Hamzehkolaei, N. Safaeian;Malekzadeh, P.;Vaseghi, J.
    • Steel and Composite Structures
    • /
    • v.11 no.4
    • /
    • pp.341-358
    • /
    • 2011
  • This paper presents the effects of thermal environment and temperature-dependence of the material properties on axisymmetric bending of functionally graded (FG) circular and annular plates. The material properties are assumed to be temperature-dependent and graded in the thickness direction. In order to accurately evaluate the effect of thermal environment, the initial thermal stresses are obtained by solving the thermoelastic equilibrium equations. Governing equations and the related boundary conditions, which include the effects of initial thermal stresses, are derived using the virtual work principle based on the elasticity theory. The differential quadrature method (DQM) as an efficient and robust numerical tool is used to obtain the initial thermal stresses and response of the plate. Comparison studies with some available results for FG plates are performed. The influences of temperature rise, temperature-dependence of material properties, material graded index and different geometrical parameters are carried out.

Free vibration investigation of functionally graded plates with temperature-dependent properties resting on a viscoelastic foundation

  • Abdeldjebbar Tounsi;Adda Hadj Mostefa;Amina Attia;Abdelmoumen Anis Bousahla;Fouad Bourada;Abdelouahed Tounsi;Mohammed A. Al-Osta
    • Structural Engineering and Mechanics
    • /
    • v.86 no.1
    • /
    • pp.1-16
    • /
    • 2023
  • The free vibration of temperature-dependent functionally graded plates (FGPs) resting on a viscoelastic foundation is investigated in this paper using a newly developed simple first-order shear deformation theory (FSDT). Unlike other first order shear deformation (FSDT) theories, the proposed model contains only four variables' unknowns in which the transverse shear stress and strain follow a parabolic distribution along the plates' thickness, and they vanish at the top and bottom surfaces of the plate by considering a new shape function. For this reason, the present theory requires no shear correction factor. Linear steady-state thermal loads and power-law material properties are supposed to be graded across the plate's thickness. Uniform, linear, non-linear, and sinusoidal thermal rises are applied at the two surfaces for simply supported FGP. Hamilton's principle and Navier's approach are utilized to develop motion equations and analytical solutions. The developed theory shows progress in predicting the frequencies of temperature-dependent FGP. Numerical research is conducted to explain the effect of the power law index, temperature fields, and damping coefficient on the dynamic behavior of temperature-dependent FGPs. It can be concluded that the equation and transformation of the proposed model are as simple as the FSDT.

Thermo-mechanical vibration analysis of temperature-dependent porous FG beams based on Timoshenko beam theory

  • Ebrahimi, Farzad;Jafari, Ali
    • Structural Engineering and Mechanics
    • /
    • v.59 no.2
    • /
    • pp.343-371
    • /
    • 2016
  • In this paper thermo-mechanical vibration analysis of a porous functionally graded (FG) Timoshenko beam in thermal environment with various boundary conditions are performed by employing a semi analytical differential transform method (DTM) and presenting a Navier type solution method for the first time. The temperature-dependent material properties of FG beam are supposed to vary through thickness direction of the constituents according to the power-law distribution which is modified to approximate the material properties with the porosity phases. Also the porous material properties vary through the thickness of the beam with even and uneven distribution. Two types of thermal loadings, namely, uniform and linear temperature rises through thickness direction are considered. Derivation of equations is based on the Timoshenko beam theory in order to consider the effect of both shear deformation and rotary inertia. Hamilton's principle is applied to obtain the governing differential equation of motion and boundary conditions. The detailed mathematical derivations are presented and numerical investigations are performed while the emphasis is placed on investigating the effect of several parameters such as porosity distributions, porosity volume fraction, thermal effect, boundary conditions and power-low exponent on the natural frequencies of the FG beams in detail. It is explicitly shown that the vibration behavior of porous FG beams is significantly influenced by these effects. Numerical results are presented to serve benchmarks for future analyses of FG beams with porosity phases.

Thermal stability analysis of temperature dependent inhomogeneous size-dependent nano-scale beams

  • Bensaid, Ismail;Bekhadda, Ahmed
    • Advances in materials Research
    • /
    • v.7 no.1
    • /
    • pp.1-16
    • /
    • 2018
  • Thermal bifurcation buckling behavior of fully clamped Euler-Bernoulli nanobeam built of a through thickness functionally graded material is explored for the first time in the present paper. The variation of material properties of the FG nanobeam are graded along the thickness by a power-law form. Temperature dependency of the material constituents is also taken into consideration. Eringen's nonlocal elasticity model is employed to define the small-scale effects and long-range connections between the particles. The stability equations of the thermally induced FG nanobeam are derived via the principal of the minimum total potential energy and solved analytically for clamped boundary conditions, which lead for more accurate results. Moreover, the obtained buckling loads of FG nanobeam are validated with those existing works. Parametric studies are performed to examine the influences of various parameters such as power-law exponent, small scale effects and beam thickness on the critical thermal buckling load of the temperature-dependent FG nanobeams.